Pairing Vibrations Study with the Time-Dependent Hartree-Fock-Bogoliubov theory

TL;DR

This study investigates pairing vibrations in oxygen and calcium isotopes using the time-dependent Hartree-Fock-Bogoliubov method, revealing insights into low-lying modes and giant pairing vibrations with results aligning with quasiparticle RPA calculations.

Contribution

It applies the TDHFB approach with specific energy functionals to analyze pairing vibrations, including the observation of giant pairing vibrations in oxygen isotopes.

Findings

Overall agreement with quasiparticle RPA for oxygen isotopes

Giant pairing vibrations observed in oxygen but not in calcium isotopes

Differences increase with neutron number

Abstract

We study pairing vibrations in $^{18,20,22}$O and $^{42,44,46}$Ca nuclei solving the time-dependent Hartree-Fock-Bogoliubov equation in coordinate space with spherical symmetry. We use the SLy4 Skyrme functional in the normal part of the energy density functional and a local density dependent functional in its pairing part. Pairing vibrations are excited by two-neutron transfer operators. Strength distributions are obtained using the Fourier transform of the time-dependent response of two-neutron pair-transfer observables in the linear regime. Results are in overall agreement with quasiparticle random phase approximation calculations for Oxygen isotopes, though differences appear when increasing the neutron number. Both low lying pairing modes and giant pairing vibrations (GPV) are discussed. The GPV is observed in the Oxygen but not in the Calcium isotopes.